My Mavic 2 Pro Crashed

[Jackcutrone]

SAR104 - what do you use to get those spiffy graphs? And do you have a p ost somewhere explaining how to do I?

Re: OP - it is almost always pilot error, sometimes in flight, sometimes in pre-flight.

 

[sar104]

SAR104 - what do you use to get those spiffy graphs? And do you have a p ost somewhere explaining how to do I?

Re: OP - it is almost always pilot error, sometimes in flight, sometimes in pre-flight.

The data are from the txt and DAT files. The calculations and graphical display are done in Wavemetrics Igor Pro.

I've been writing a guide to log analysis for just about one year now, and still haven't completed it. There is no simple recipe, especially for some of the more useful calculations such as those required to compare GPS and IMU positions and velocities. Changing attitude parameters from earth to aircraft frame of reference, to look at velocity as a function of stick input for example, requires some simple quaternion algebra - not particularly difficult but not something the average non-scientist/mathematician is going to tackle. If you have any specific questions about what I'm doing I'd be happy to answer them.

 

[bikoo]

i just want to let you know the correct direction for my flight was like this photo i was in between the two buildings then it hit the right building as per the photos

 

[bikoo]

and from this photo you can see the balance in 14s is all the way to right way >>>>

 

[sar104]

i just want to let you know the correct direction for my flight was like this photo i was in between the two buildings then it hit the right building as per the photos

View attachment 54745View attachment 54746

So actually nothing at all like the recorded flight track is what you are now saying? The reason that I asked previously is that it actually matters. If that is the case then post the DAT file for the flight, which will be FLY012.DAT.

Mobile device DAT file: How to retrieve a V3.DAT from the tablet

 

[bikoo]

Thank you so much Sar104, kindly find the attached

 

[AeroMirage]

View attachment 54713

OUCH>>>>>>>

 

[bikoo]

OUCH>>>>>>>

Seems gps issue

 

[sar104]

OK - based on your new flight description and thus discarding the GPS data entirely, we can estimate position purely from the two IMU datasets:



They don't agree perfectly, probably due to bias uncertainties, but they broadly agree on a flight path consistent with the one that you described. That's also consistent with scrambled GPS reception, most likely due to building reflections and poor sky view:



As a result, it appears that the FC was completely confused by the position data it was receiving, and was heading north when it thought it was heading south. That's a hazard of launching with poor GPS reception in a location with a very poor sky view and multiple vertical reflectors (buildings).

 

[bikoo]

OK - based on your new flight description and thus discarding the GPS data entirely, we can estimate position purely from the two IMU datasets:

View attachment 54807

They don't agree perfectly, probably due to bias uncertainties, but they broadly agree on a flight path consistent with the one that you described. That's also consistent with scrambled GPS reception, most likely due to building reflections and poor sky view:

View attachment 54808

As a result, it appears that the FC was completely confused by the position data it was receiving, and was heading north when it thought it was heading south. That's a hazard of launching with poor GPS reception in a location with a very poor sky view and multiple vertical reflectors (buildings).

I really appreciate your efforts, I hope DJI support can understand and give me replacement

 

[ff22]

OK - based on your new flight description and thus discarding the GPS data entirely, we can estimate position purely from the two IMU datasets:

View attachment 54807

They don't agree perfectly, probably due to bias uncertainties, but they broadly agree on a flight path consistent with the one that you described. That's also consistent with scrambled GPS reception, most likely due to building reflections and poor sky view:

View attachment 54808

As a result, it appears that the FC was completely confused by the position data it was receiving, and was heading north when it thought it was heading south. That's a hazard of launching with poor GPS reception in a location with a very poor sky view and multiple vertical reflectors (buildings).

Your charts/graphs make my head spin but thanks for explaining in somewhat understandable terms and thanks for doing this for folks.

 

[sar104]

I really appreciate your efforts, I hope DJI support can understand and give me replacement

It's worth asking them, but I would not be too hopeful. You flew in very sub-optimal conditions.

 

[bikoo]

It's worth asking them, but I would not be too hopeful. You flew in very sub-optimal conditions.

Yah but there's HW flute so let's see, since there's no enough GPS it should switch to atti mode!!
Thank you so much for ur time, I'll let u know once they get back to me

 

[mavicn00b]

I really appreciate your efforts, I hope DJI support can understand and give me replacement

With Care Refresh and a nominal fee I'm sure they will. You did get care-refresh right?

 

[FoxhallGH]

“The Home Point has been recorded. Please check it on the map.”

And she says it in such a nice way ...

 

[bikoo]

And she says it in such a nice way ...

lol

 

[bikoo]

With Care Refresh and a nominal fee I'm sure they will. You did get care-refresh right?

unfortunately i dont have this will help if it's Pilot Error. what do you think about my case!! it's not my fault.

 

[RadioFlyerMan]

For as long as drones have had GPS I have found it is best to let them sit on the ground a full minute or 2 to insure you get a good GPS signal lock, and to let the IMU sensors warm up properly.

As stated previously. watch the GPS signal strength. If it goes in and out while letting your drone sit on the ground for a minute after you turn it on, then be aware that it may not hold its position after take off.
If your in a confined area or for some other reason don't feel comfortable flying without GPS than don't take off.

Also note VPS warning for dark areas.

Exactly!

 

[bikoo]

i have good news, DJI will cover the repair or the replacement under warranty

special thanks to Sar104 for all your time the information you provided.

 

[sar104]

i have good news, DJI will cover the repair or the replacement under warranty

special thanks to Sar104 for all your time the information you provided.

That's good news. Don't forget to pay attention to the issues this raised however, because it did not look like an equipment problem and I suspect that any replacement would behave similarly in that situation.